Detector circuit



Patented Feb. 9, 1926.

umT ojsTA s PATENT OFFICE,

JOSEPH HERMAN, O NEW YORK, N. Y.,.ASSIGNOR T AMERICAN TELEIBHONE AND TELEGRAPH COMPANY, A (CORPORATION OF NEW YORK.

DETECTOR CIRCUIT.

' Application ,file'd October 13, 1923. SeriaI'NO. 668,384.

To all whom it may concern:

Be it known'thatfI, JOSEPH HERMAN, a

citizen of the Republic of Au'stria,residing at New York, in the county of New York and- State of New York, have invented certain Improvements in Detector Circuits, of whichtheffollowing is a specification.

receiving relay circuits This invention relatesto detectorqcircuits and more particularly to improvements in {to be used in connection with'detectors.

Heretofore in multiplexcarrier systems in which the carrier channels'were employed for the transmission of telegraph signals it has been found necessary to use two or more tubes in the detector circuit in order to obtain sufficient detected current to operate the telegraph receiving relay. It is one of the objects of the presentinventionto provide a detector circuit in which a single vaccum' jttibe detector may be employed and in which the action of the polar receiving relay will be more efficient.

Other and further objects of the invention will be clear from the following description'; when read in connection with the accompanying drawing, Figure 1 of whlch illustrates the circuit arrangement of detector circuits of thetype hereinbefore employed in connection with carrier telegraph systems; Fig. 2 of which is. a circuit diagram illustrating the improved form of detector circuit and Figs. 3 to 7 of which are curves illustrating the operation of the detector circuit of Fig. 2. v t

In order that the present invention may be clearly understood it is desirable that thetype of detector circuit which is now in common use in carrier systems be explainedand in this'connection reference is employed for detecting purposes for the reason that these tubes have a large current output and are therefore capable of furnishing suii'icient operating current for the type of polar relay in common use for telegraph receiving purposes. The so-called L tubes are not, however, as" sensitive as might be desired and for this 'reason'it is necessary to use two tubes'in tandem. The polar receiving relay PR comprises six winding units, numbered 13 to 18 inclusive, WhlCh units are so arranged as to form three mainwindings. The six winding units in relays of this type are usually'of two kinds,

four of the units being ofthe type known as line windings and two of the units being of the type known as vibratory windings. So far as the, presentinvention is concerned the terms line and vibratory have no significance and these terms will only be used for the purpose of iden- 'tifying the units. Each line winding unit in practicecomprises about 2,000 turns having a resistance-of about 200 ohms. The

vibratory winding units, which are com posed of the outer layers of-t-he coils of the relay, only have about 800 turns'each and a resistance of about 115 ohms.

The three main windings of the relay,

whichare formed from the six units above referred to, perform three separate and distinct functions in the operation of the receiving relay of Fig. 1. One of these windings, comprising the line units 15 and 16 1s included lirectly in the output circuit-o the detector tube D and functions as the operating winding of the relay. .The other two line units 13 and 14 form the so-called kick winding which is connectedinto a local circuit associated with the output circuit of the detector Dthl'Ollgll a transformer comprising windings 11 and 12. The two so-called vibratory windings 17 and 18 are 7,

connected in a local circuit with a source of direct current and constitute the biasing windings of the system.

The detector circuit is so arranged that when high frequency oscillations are not being-received the grid potential will be of such value as to prevent the flow of any direct current in the output circuit through the windings 15 and 16. lVhen high frequency oscillations are received, however, a

directcurrent pulse will flow through the operating winding comprising the units 15 and 16 to shift the armature of the polar relay to its opposite position. The value of windings is such as to produce av biasing force in a direction opposite to the detected operatingforce, the magnitude of the biasing force being substantially one-halt that of the operating force. The detected pulse of current, therefore, produces a resultant force tendng to sliitt'the armature to its alternative position, 'said force being substantially equal but opposite in sign to the normal biasin force." The purpose of the .so-called kiclr' winding is to produce a kick at the beginning and at the end ottlie detectedpulse (it operating.curreiit for the purpose of making tlieaction' ofthe arma-- ture quicker and inorefreliable. The kick impulse is produced byv the action of the transformers 11 and 12,. due to the change in the value of the current flowing in the opera ating circuit.

Referring now to Fig. 2 which illustrates a circuit arrangement embodying the principles oftli'e present invention, it will be seen that the detector D comprises a single tube ct"v these-called V type. In order to use a single tubefor detecting purposes in commercial carriertelegraph'circuits of the type now in coininoiiuse lt'jS necessary that the detectingtube be very sens'tive. The so-called V type of tube is much more sensitive than the L type tubes heretofore employed-in tanden'i, 1

but owing to its increased sensitivity the ac tual amplitude of the output current s much smaller than that of the less sensitive tubes. Itis, tli ere'iore, necessary tore-design the polan frelay set so that the relay will operate efiiciently with the smaller. detected operating currentssupplied by the single dc.- tecting tulie D. Accordinglyrit .is proposed in Fig. 2 to supplement the detected operat' ing current with a holding current controlled byl'the armature of the polar relay in its operation. This necessitates the use of at least one of the winding units of the relay asthe holding wind ng and in order to economically use the remaining windings itis proposed to eliminate the special kick winding" and utilize the biasing w ndiiig and the operating winding; as the kick, windings of'thc relay system. i y

Accordingly. as illustrated in Fig. .2, the four line winding units 13, 14. 15 and 16 are connected in series with each other and with the ll battery of, the detector tube, so thatthese tour windings constitute the main operating winding. One of the so-called vibratory windings i7 is used as the hold ing winding and is connected in circuit with the armature of the relay so that as the armature shifts from one position to the other to connect positive or negative current to the subscribers loop, positive or negative current will be caused. to low tl'irough the. holding circuit in such a direction as to .cnd to hold the armature against the contact to larva which it has been shifted. This prevents chattering and other unsatisfactory opera tion of the relay. The other vibratory Wind ing 18 is connected in a local circuit with theB battery supply so that this winding The transtornierisinlthe nature of an autotransformer with thcwvindings 11 and 12 acting as'tlie primary winding of the trans former and the winding 12 connected in a local A-C circuitwith the operating winding and the biasing windingof the relay.

lhese two relay windings being included in the local i ls- C circuit function to, produce a kick effect upon the relay as a result of the action at theiransforiner windings Ill and 12 at the beginning and end of the detected impulse.

"lhe operatioii of the windings of the relay will be clear from the curvessliown i1i- Figs. 3 t r inclusive, which curves show the magnitude and character of the forces acting upon the armature oi the relay as a result ot the current flowing in the several windings. Let usassume that no high Erequency oscillations are IJGCGlVGd ClHP HI Q' the spacing interval and. that the transmission of high frequency oscillations corresponds to a marking signal.. The normal gridpo' tei tial of the detector tube D otFig. 2 is so arranged that no current, will-flow in the output circuit through the transformer winding 11 and the foui' line' windings 13 to 16 inclusive during the spacing interval.

ll-hen the train of high frequency waves is.

received, however, a detected impulse of current will flow, as indicated at 25 in Fig. 3-. The biasing current through the winding 18 is in such a direction, as illus-.

trated in. Fig. i as to produce a pull upon the armature oppositeinsign to the force resulting from the marking signal 25. The operation of the arn'iature produces a current wave in the lioldingwin'ding. 17 having the characteristics illustrated in Fig. 5.

The pull produced upon tlieai'niature lSdIi sucha direction as to tend to hold it against the contact to which it has been shifted and consequently, during'tlie marking interval, the force is in the saineqtlirection as the force produced by the operating current. During the spacing interval, however, an equal force is exerted upon the armature in the direction opposite to that produced by the operatinc" current. The magnitudes of the two holding 'l OICCSVtII'Q substantially equal and preterably "are of the same order as that of the spacing interval the effects of the bias mg and holdmgtorces are cumulative and the resultant force should be opposite in the biasing Force in the winding 18. During ing interval.

sign to but of substantially the same magnitude as the operating force durmgthe mark ing and holding forces should oppose and substantially neutralize each other during the marking interval.

In addition to the forces above discussed theaction of the auto-transformer .1112

' produces a kick impulse at the beginning produced at the end and the end of the marking signal, as illustrated in Fig. 6. The kick impulse occur-' ring at the beginning of the' marking period produces an eflFect in the biasing winding '18 which is opposite in direction to'the biasthe biasing force. .A biasing impulse is of the markin period in such a direction as to be cumulative with respect to the biasing force, as indicated in the dotted lines in Fig. 4. Likewise, forces are produced in the operating winding comprising the units 13 to 16 inclusive at the beginning and the end of the marking inter val, as indicated inddtted lines in Fig. 3. The cumulative effect will produce a resultant-force having substantially the characteristics indicated in heavy lines in Fig. 7 Analysis of this curveshows that a true polar action is given to the relay, a resultant force" in one directionoccurring during the marking interval and an equal and opposite force occurringdur ingthe spacing interval. At the beginning and end of the interval resultant force operating upon the armature. I 5 By re-arranging the winding units of thestandard polar receiving. relay in the manner indicated in Fig.2, the relay oper' ates efiiciently in response to the relatively small current supplied by the V type detector tube. i

It will be obvious that the general principles herein disclosed may be embodied in many other organizations widely dlfferentdeparting as defined supplied w th a biasing current, and an.

auxiliarv holding winding continuously supplied with current in a direction determined by the posit on of the relay armature.

2. A detector circuit compr sing a highly sensitive detector tube having a small o'perating current and a polar relay associated On the other hand, the bias! biasing and holding windings producing mg current, thereby tending to neutralize of. all lots these forces.

ing winding circuit inductively associated with the out-.

an efiective kick impulse occurs in thesame d rectionas the I with said detector, said, polar relay having. a

large operating winding in the output cirf cuit of the detector and responsive to the detected operating current to shift the armature of the relay, a small biasing. winding suppliedwith a biasing current, and an auxiliary holding winding continuously supplied with current in a direction determined by the position of the relay armature, said forceswhich-oppose each other when operating current is flowing through the operating winding and which assist each other when no operating current is flowing.

3. A detector circuitconiprising a highly sensitive detector. tube having a small operating current and a polar relay associated with said detector, said polar relay having alarge operating winding in'the output circuit of the" detector and responsive to. the detected'operating current to-shift the armatureof the relay, a small biasing winding supplied with a biasing. current, and an auxiliary holding winding supplied with current in *a direction determined by the position of the relay armature, said operatbeing included in a local kick put side'of the detector.

4. A detector circuit comprising a highly sensitive detector tubehaving a small operating current and a polar relay associated with said detector, said polar relay having a large operating winding in the output circuit of the detector and responsive to the detected operating current to shift'the arma-v. ture of the relay, supplied with 'a biasing current. and an auxiliary holding winding supplied with current in a direction determined by the position of the relay armature, said biasing winding being included in a local kick circuit inductively associated with the output side of the detector.

5. A detector circuit comprising .a highly sensitive detector tube having a small operating current and a polar relay associated with said detector, said polar relay having a large operating winding in the output circuit-of the detector and responsive to the .deteeted operating current to shift the armature of'the relay. a small biasing winding supplied with a biasing current. and an auxiliary holding winding supplied with fcurreut in a direction determined by the position of the relay armature, said operata small biasing winding ing and biasing windings being included in a local" kick circuit inductively associated with the output side of the detector.

6. A detector circuit comprising a highly sensitive detector tube having a small operating current and a polar relay assoc ated with said detector, said polar relay having a large operating winding in the output circuit of the detector and responsive to the A; LMMLWZH dufzuurtmi npm'ating" current who shift the, am-

M 100213. kick circuit inductively associated with Mm nhtput side 0:1? tlwk lutcctor through an auto4:1'nnsfin11m: collimation.

In tesiinmny whereof, I lmvc signud my name to this spugificntion MUS 11th day of Uctoben 1993.

- JUSEPH HERMAN. 

